The Roman Rule Testis Unus Testis Nullus in the Canonical Codified Sources Regulating Ordinary Proceedings

This article presents the issue of the Roman procedural rule testis unus testis nullus in the canonical sources regulating ordinary proceedings. The rule on witnesses found its place in the 1917 Code of Canon Law, and was later repeated in the 1983 Code of Canon Law and in the 1990 Code of Canons of the Eastern Churches. It was included in the section of the code containing canons regulating contentious proceedings and has been applicable as a general norm. It was pointed out that the Roman principle of witnesses had been a very important reference in the legal tradition of canon law for centuries, but it was not applied in a formalistic manner and deviations in its application were allowed. However, this practice was not entirely in line with the biblical tradition, nor with the Roman tradition, especially since the issuance of the imperial constitution by Constantine the Great in 334. This article attempts to answer the question why the canonical tradition, which has adhered to the requirement of testis unus testis nullus for centuries, does not do so in an absolute manner, allowing for the possibility of exceptions. In this regard, selected fragments of two imperial constitutions of Constantine the Great are presented and analysed. They regulated the issue of the universal requirement of double testimony in imperial law and the admissibility of a single testimony delivered by a bishop.